1. Field of the Invention
This invention relates generally to diagnostic and therapeutic apparatus and methods in gynecology, and more particularly to diagnosing and relieving the symptoms of incontinence in women.
2. Prior Art
(a) Causes of Incontinence--Inability to deter the flow of urine from the bladder is a common phenomenon in women, particularly older women. Such inability to contain urine is termed "incontinence." Roughly half of elderly women are incontinent.
An incontinent woman usually has an adequate reservoir (the bladder) for urine, but the biological "valve" is for one or another reason inadequate to prevent discharge of urine. The "valve" that normally performs this function is the urethra--the duct through which the bladder is normally emptied during urination--in conjunction with the muscle or sphincter that surrounds the urethra.
The most frequently encountered causes of incontinence in women may be classified as pathogenic, anatomical and neurological. Before incontinence in a particular woman is treated, its cause must be ascertained. Not only is appropriate treatment for each kind of incontinence ineffective against other kinds of incontinence, but in some instances appropriate treatment for one type is counterproductive with respect to other types.
Incontinence that is pathogenic--caused by infection--is readily identified in ways that are outside the primary scope of my invention. (As will be seen, my invention is compatible with procedures for checking the possibilities of pathogenic incontinence.)
Anatomical and neurological incontinence, however, are readily confused by diagnosticians.
Historically, distinguishing between them has been attempted by direct observations, and very recently it has been accomplished by sophisticated instrumentation. In addition, my copending patent application Ser. No. 661,087 describes an inexpensive diagnostic apparatus that is extremely effective in facilitating the earlier, direct form of observation. All three of these systems will be described below. Unfortunately the earlier forms of direct observation are subject to several obstacles and inaccuracies, whereas the instrumentation is subject to such extremely high cost as to be accessible only to medical centers (as distinct from individual clinicians)--and even so is not free from certain inaccuracies and other disadvantages.
The diagnostic aid described in my copending application is superior to the earlier forms of direct observation and the instrumentation, but it is somewhat more time consuming than the present invention. It is also limited to diagnostic use, whereas the present invention provides symptomatic relief as well.
To understand the shortcomings of these other technologies it is necessary to understand the behavior and causes of anatomical and neurological incontinence. Both of these types appear in response to bodily stress, and particularly as reactions to a relatively abrupt increase in pressure within the abdomen.
(Traditionally the anatomical type of incontinence has been identified as "genuine stress incontinence" though both of these two types are in fact triggered by stress, and it may therefore be more accurate to describe both as, at least, "stress incontinence.")
A cough, sneeze or laugh is often the stimulus for such a pressure increase, but in more advanced stages of incontinence the patient may be unable to contain her urine even against pressure increases such as are incurred through light exercise: lifting, bending down, running, or even merely walking. Since these sorts of stress are basic to everyday living and use of the body, it will be apparent that advanced stress incontinence is virtually debilitating. Patients in which such conditions are untreated must resort to adult-size diapers or other cumbersome, relatively unsanitary, and potentially embarrassing appliances.
Stress-induced pressure increases, in normal women as well as women suffering from both types of stress incontinence, are transmitted to the bladder (though by different mechanisms), causing the pressure within the bladder to rise. In normal women, however, the pressure incurred by coughing, exercise, and so forth is exceeded by the pressure within the urethra.
When normal individuals are not urinating, the urethra is held closed by voluntarily controlled musculature (the sphincter surrounding the urethra), with the aid of surrounding anatomical structures. This musculature and other anatomical features produce a pressure within the urethra that exceeds any pressure ordinarily produced by stresses (pressures) transmitted to or arising in the bladder.
The higher pressure within the urethra stands off the liquid stored in the bladder, preventing the liquid from being discharged through the urethra and thereby out of the body.
Another important factor operates in aid of the muscles and other features in the normal woman: both the bladder and the urethra are subjected in common to various pressures within the abdomen. Thus for example, pressure arising from a cough is applied to both the bladder and the urethra. With regard to the urethra, the pressure under discussion here is lateral or radial, pushing inwardly from the sides of the urethra and so tending to hold the urethra closed. Consequently the tendency of any particular pressure to squeeze fluid out of the bladder is directly counteracted by the tendency of that selfsame pressure to squeeze the urethra shut.
There are primarily two ways in which this normal control system can fail: (1) the muscles and the structure that normally hold the urethra closed can become weak, and (2) the body can malfunction in such a way as to amplify the pressure increase within the bladder. In either of these abnormal situations, the pressure within the urethra is insufficient to stand off the pressure in the bladder--and urine is forced outward from the bladder through the patient's urethra.
The first of these two kinds of failure is due to three interrelated anatomical weaknesses: the sphincter muscle that squeezes the urethra closed is no longer able to exert the normal amount of force; the bladder opening at the top of the urethra, and the inner (or proximal, in medical terminology) end of the urethra have lost their support; and the musculature structure around the base of the urethra and vagina has lost its tone. (This structure is the levator ani sling--a hammock-shaped musculature which extends across and closes off the abdomen, except for the vaginal, urethral and anal orifices.) These weakenings probably occur either as a result of childbirth or as part of the general deterioration of bodily structures with advancing age, or both.
The inner end of the urethra, in any event, is broadened--practically becoming part of the bladder, so that the urethra itself is effectively foreshortened. The urethra also undergoes "prolapse"--it falls down or slips from its normal position--and the outer end of the urethra is virtually buried in the levator ani sling. It is this part of the urethra that is surrounded by the urethral sphincter.
The resulting phenomena may be viewed in a relatively mechanical way: a sudden increase in pressure within the abdomen (as with a cough) is transmitted to the bladder, but not to the urethra. The urethra in its prolapsed position is shielded by the surrounding levator ani sling from the pressure within the abdomen, and bladder pressure becomes greater than urethral pressure. In addition, the urethral sphincter is relatively ineffective in its function as a valve. Due to the foreshortening of the urethra, the full weight of the contents of the bladder is brought to bear more directly than normal upon this already-handicapped control system. Due to these factors in combination, urine is forced outwardly through the urethra.
Anatomical incontinence thus arises from selective application of intraabdominal pressure--application to the bladder but not to the urethra--compounded by weakened sphincter action and a downwardly displaced hydraulic loading. This is known as "genuine stress incontinence." It can be treated surgically, or to a generally unsatisfactory degree by prosthetic therapy, but not by administration of medicines. The prosthetic approach will be discussed in some detail later.
Surgical procedures suspend the vagina and thereby pull upwardly on the urethra to return the urethra to the region of normal intraabdominal pressure, above the levator ani sling. The rationale is to reequalize the application of intraabdominal pressure. Approximately one hundred fifty different operative procedures have been devised. Certain of these procedures are recognized as effective; however, surgery has several limitations.
Surgery is always a relatively drastic and expensive alternative. It may be entirely contraindicated for the very elderly or others whose general condition is frail. Moreover, surgery is to be avoided if the patient's etiology is not "anatomical incontinence," since surgery can often aggravate incontinence arising from other causes. Finally, there is often a protracted delay while the patient awaits a surgical date; during this time the patient requires some relief.
The second of the two kinds of failure enumerated above, the amplification of the stress-induced pressure increase, can occur in a woman whose urethral pressure is ample to withstand the abdominal pressure increase that is directly associated with a cough, sneeze, laugh, or even vigorous exercise. In this second kind of incontinence, however, the increased pressure within the bladder triggers nerve signals, and these nerve signals abnormally stimulate the bladder to contract. The contraction of the bladder in turn raises the pressure within the bladder very severely-- to a level considerably greater than that produced directly by the stress.
The nerve signals triggered by the original pressure increase in the bladder may travel to the brain, causing return signals to the bladder along nerve paths normally used by the patient to squeeze the bladder and thereby help expel urine from the bladder. It is also possible that the nerve signals cause a more-localized chain reaction of spasms that eventually return to squeeze the bladder. Whatever the specific mechanism, this type of incontinence is characterized by a time delay of at least three to five seconds, and sometimes as long as fifteen to twenty seconds, between the originating stress and the responding contraction and discharge. In addition to the difference in timing, this type of incontinence also is usually characterized by a greater volume of discharge.
This type of stress incontinence is often called "bladder instability." It can be treated by administration of medicines, but not by surgery or prosthetic therapy. In fact, attempts to correct it surgically often result in aggravating the condition.
(b) Diagnostics: the "Stress Test"--A historically common method of determining which type of incontinence a woman has is the so-called "stress test" introduced by Doctors Bonney, Marshall and Reid. In the stress test the patient's bladder is filled with fluid (often a quarter of a liter of salt solution) and she is asked to cough. If fluid is discharged from her urethra immediately, the patient is diagnosed as suffering from "genuine stress incontinence" and requiring surgery, whereas if there is a delay the patient is diagnosed as having "bladder instability" and requiring medication. The test of course relies upon the difference in timing between the two kinds of reaction. Unfortunately this so-called "stress test" is flawed in several ways.
First, about half of incontinent women are continent when lying down. This fact results from the force of gravity on fluid in the bladder and on other bodily organs near the bladder. In a standing patient the proximal end of the urethra is essentially at the bottom of the pool of fluid in the bladder, and gravity adds substantially to the stress-induced pressure at the proximal end of the urethra. Furthermore, the weight of organs that are above the bladder tends to be applied to the bladder when the patient stands.
When the patient reclines, however, the rotation of the bladder and surrounding structures places the proximal end of the urethra much closer to the upper surface of the fluid in the bladder, or even above the upper surface, so that gravity makes no substantial addition to the stress-induced pressure at the proximal end of the urethra. At the same time there are fewer organs disposed to press upon the bladder when the patient reclines.
Hence the test must be conducted with the patient standing. Unfortunately, however, it is very undesirable to perform such a test with the patient standing. The standing patient will not generally be able to spread her legs sufficiently to allow the diagnostician a clear view of the distal (outer) end of the uretha. Consequently the diagnostician usually inserts her or his fingers within the patient's labia (the folds of flesh covering the vaginal outlet) to determine when that area is wetted by discharge of fluid. Under such conditions it is extremely difficult to accurately determine the timing of the discharge relative to the stress, especially considering that in some patients suffering from bladder instability the time delay is only three seconds.
Secondly, in a setting such a doctor's office the patient is often anxious. This often causes the voluntary sphincter of the uretha to go into involuntary spasm (that is, to squeeze the uretha shut), which obstructs the flow of fluid from the bladder. It has been shown that one-third or more of incontinent women may be unsable to demonstrate incontinence under these circumstances. After leaving the doctor, however, the patient may again become incontinent.
This problem is aggravated by the fact that the patient must stand during the test, essentially confronting the doctor, with the doctor's fingers placed within the patient's labia. This confrontation accentuates the patient's realization that any fluid lost will wet the doctor's fingers, and such behaviour of course contradicts all normal social schooling. As a result, in addition to the involuntary anxiety spasm discussed in the preceding paragraph, many patients may actually consciously squeeze the urethral sphincter more forcefully than they may normally squeeze during coughing, sneezing, exercising, etc.--thereby defeating the test.
Thirdly, many women have relatively large labia, which can act as a dam to discharge of fluid from the urethra. This effect makes it very difficult to determine whether fluid from the bladder is lost immediately or after a delay.
Fourthly, many women are obese, and the compound obstructions formed by rolls of flesh and folds of skin at the thighs of an obese patient similarly dam the fluid emerging from the urethra. The timing determination is accordingly impeded.
Fifthly, in any observation of biological phenomena there is a certain amount of imprecision. Diagnosticians may find that a discharge occurs with a seeming delay of one or two seconds, which does not correspond neatly to either category of stress incontinence. Similarly diagnosticians may find that some discharge occurs immediately after stress, and that an additional discharge "seems" to occur later. It must be realized that some women suffer from both types of incontinence, which would account for a dual discharge, but it is extremely difficult to determine reliably that a second discharge has occurred after the labia and the diagnostician's fingers are already wetted.
(c) Diagnostics: Other Direct Observations--Partly as a result of the difficulties just described, diagnosticians usually perform other tests to gather additional information on the patient's anatomical condition. In particular, one common test--familiarly known as the "Q-tip test"--involves inserting a "Q-tip" cotton swab partway into the urethra, while the patient is lying on her back in the customary pelvic-examination position, and instructing the patient to bear down (as in defecation). In these circumstances the swab initially is generally horizontal, and deflects upward when the patient bears down.
In a normal patient the upward deflection does not exceed roughly thirty degrees. In the abnormal anatomical condition that gives rise to so-called "genuine stress incontinence," however, the upward deflection can approach ninety degrees. Since many diagnosticians are accustomed to including this test in their "work up," it is desirable to ensure that any new procedure proposed is compatible with--or, preferably, facilitates--some version of the "Q-tip test."
Similarly, it is generally routine to take a sample of urine directly from the patient's bladder. Such a sample is helpful in checking for pathogenic conditions, since it is less likely than an excreted sample to be contaminated by chance unsanitary conditions within or just outside the patient's labia. Consequently in any new procedure the obtaining of such a sample should be facilitated.
(d) Diagnostics: Modern Instrumentation--The ambiguities in the now-classical "stress test" have led to introduction of electronic instrumentation for determining essure relationships between the bladder and the proximal end of the urethra.
Such instrumentation generally consists of (1) a first pressure sensor that is inserted entirely through the urethra into the bladder, to sense the pressure within that organ; (2) a second pressure sensor that is inserted partway through the urethra, to sense the pressure along that duct, and (3) electronics and display devices for determining and recording those two pressures as they change with time, and in some instruments for also determining and recording certain relationships between those pressures.
The pressure sensors used may be of two different types. First, a pressure sensor may consist of (a) a small transducer, positionable within the bladder or urethra, that controls an electrical resistance or an electrical voltage source--together with (b) electrical leads for directing to the exterior of the body electrical signals related to the sensed pressure, and (c) a rod or the like for inserting the transducers and leads into position, and holding them in position, for measurement.
The other type of pressure sensor may consist of (a) a pair of tubes inserted into the bladder and urethra respectively, and (b) pressure-measurement devices attached to the ends of the tubes that are outside the body, to measure the pressure transmitted through the tubes while the tubes are held in position. With this type of sensor, the tubes are usually provided in the form of a single tube structure with parallel channels within it, and separate openings spaced along the tube near its proximal end.
In use of these instruments, the pressure sensors (of either type) are inserted together into the urethra while the patient reclines in the usual pelvic-examination position. One sensor is advanced approximately two to three inches forward of the other sensor, while the instrument operator observes the changing pressure readouts from the instrument. When the readout from the forward or proximal sensor decreases (indicating that the sensor has passed from the urethra into the bladder) but the readout from the rearward or distal sensor remains higher (indicating that this sensor has not yet reached the bladder), the insertion is stopped and data are taken.
In one very expensive unit, the instrument operator advances the sensor pair into the urethra and bladder, and then the apparatus (rather than the operator) automatically withdraws the catheter at a regular velocity, while measuring and recording the pressure relationships between bladder and urethra.
In other parts of the diagnosis the patient is instructed to cough, laugh, exercise, or otherwise incur abdominal stress, and the sensor measurements are recorded as they respond to the stress.
Instruments of this type are operationally preferable to the "stress test." The sensors can be emplaced while the patient is lying down and are relatively unintrusive, making insertion fairly easy.
Because the apparatus is very sensitive and relies upon pressure measurements rather than actual discharge of urine, it appears from the literature that for some patients the entire test can be successfully (that is, accurately) conducted while the patient reclines.
Yet modern instrumentation for stress-incontinence diagnosis is unsatisfactory in at least four ways.
First, there remains a very large fraction of the population of incontinent patients whose incontinence is masked by the patients' lying down.
Secondly, the equipment is prohibitively expensive for use by individual clinicians. The cost for one operational device ranges roughly from $7,000 to $50,000, depending upon the degree of automaticity desired. Modern medical philosophy, however, for very good reasons favors acquiring as much information as possible in the doctor's office, rather than in the hospital or large-scale medical center.
Although this instrumentation has found an effective market among high-volume diagnostic laboratories such as those found in medical centers, even as evaluated by these facilities such an instrument is inordinately expensive.
Thirdly, its operation is surprisingly time-consuming, requiring generally an hour to an hour and a half for full diagnosis of each patient--though only a part of this time is occupied by the actual testing. This inordinate consumption of time is wearing on the patient, and also is expensive in terms of laboratory personnel.
Fourthly, many a patient (particularly among the elderly) finds it personally degrading or offensive to have her genital region connected to a machine. This is particularly true if a cost-conscious technician, having set up the test, goes off to tend to other business--leaving the patient to lie for an hour with wires trailing from her vulva to a box of electronics. Resulting psychological effects can disturb the measurement.
Finally, in a relatively small number of patients, the tube or rod used to advance the forward sensor into the bladder may irritate the opening of the urethra into the bladder, and this irritation may cause spurious indications from the instrumentation. In particular, such irritation may have a slight tendency to produce an emulation of bladder instability, or to suppress an already existing tendency toward bladder instability. On the other hand, such irritation may also have some very slight tendency to stimulate the urethral sphincter to close either more or less forcefully than it customarily does--thereby either suppressing or emulating the observable characteristics associated with genuine stress incontinence.
Although this last-mentioned set of problems is not a major drawback, it is of some interest in relation to my invention, as will be seen.
(e) Diagnostics: Externally Stabilized Catheter--Doctors Sutherst and Brown of the University of Liverpool have described their studies of incontinence diagnosis making use of a two-channel catheter with a proximal end of one channel positioned within the urethra. 34 Urologia Internationalis 403 (1979), 52 British Journal of Urology 138 (1980), 53 British Journal of Urology 360 (1981).
In some of these studies the catheter was stabilized to the exterior of the patient's body to "prevent movement due to its weight and connections". The stabilization was accomplished by means of a "spring paper clip fixed to a flexible ring pessary . . . held between the patient's thighs".
Although these studies offered favorably high correlations between observed liquid discharge and other indications of "genuine stress incontinence," the experimental arrangements were in several ways marginal from the viewpoint of an individual clinician. The external appliance worn by the patient to stabilize the catheter would produce considerable patient discomfort if the patient were to bend, stretch, or even walk, since the urethral meatus in particular (which would be abraded by such activities) is very sensitive. Consequently in the studies described the patient could only be "tilted to the erect position on a motorised bed." Such an apparatus, of course, is far beyond the scope of equippage for the vast majority of individual clinicians.
In addition, the appliance would tend to fix the rearward end of the tube too securely to the patient's body, preventing effective incorporation of the "Q-tip test" into the diagnostic apparatus and method. As will be apparent, all of these limitations would very severely limit the feasibility of the published method for practical everyday clinical use.
(f) Diagnostics and Antiincontinence Prosthetic Therapy: the Intravaginal Pessary--I turn now from prior-art diagnostics to prior-art efforts to actually relieve the symptoms of incontinence. It will be seen, however, that some therapeutic devices have been used in a diagnostic mode.
As previously mentioned, the bladder and the urethra are subjected to various intraabdominal pressures in common in the normal woman, but selectively in the incontinent woman due to urethral prolapse. Furthermore sphincter action as such is weakened.
As also mentioned above, corrective surgery elevates the vagina and the urethra above the levator ani sling to equalize intraabdominal pressure on the urethra and bladder, thereby making the most of whatever muscular action remains. Although surgery has several serious limitations, efforts to substitute milder therapy such as prosthetic aids to erecting the urethra have heretofore been quite unsatisfactory.
One type of device, known as a "pessary," is inserted into the vagina with the object of longitudinally stretching the vagina--and with it the adjacent urethra. Thus such devices parallel in rational the surgical strategy. There are some three or four different kinds of pessaries, all with their own problems.
Generally they are all unsatisfactory in that they are very traumatic to the vaginal epithelium, causing ulceration and infection.
The various kinds are also all unsatisfactory in that the patient has been unable to insert them; they have required insertion by a physician. This is a very important drawback since it leads almost inevitably to inadequately frequent cleaning, and consequently to unsanitary conditions, infection, and aggravated ulceration.
For these reasons the prior-art pessaries considered as a group have not been very popular. Some discussion of individual kinds of pessaries, however, is in order.
Some pessaries are made of soft rubber or plastic formed on a wire skeleton. These were first introduced for the purpose of supporting a patient's uterus after prolapse. (This latter condition is a falling of the uterus into the position of the vagina, due to age or history of multiple childbirths.) It was then incidentally found that these pessaries prevented incontinence in some women. Such covered-wire pessaries generally have taken the form of a long letter "O" bent at a right angle near its top end, to form a tall vertical letter "U" that is joined at the open end to a short horizontal letter "U". Viewed from the side, the shape is thus that of an inverted letter "L".
To install this device, a physician squeezes the opposing sides of the frame together and inserts the pessary, with its short horizontal portion leading, into the patient's vagina. In principle the shorter U-shaped section fits around the patient's cervix, and ideally the physician should not let the opposing sides of the skeleton spring apart until the pessary is entirely into position.
In practice, of course, it is virtually impossible for the physician to hold the opposing sides apart after the pessary is about two-thirds inserted, so the device must be inserted the rest of the way while sprung open. It will be appreciated that there is some patient discomfort in this process, and possible trauma as well. Moreover, since the bottom or distal end of the device is a solid transverse bar across the mouth of the vagina, it is exceedingly difficult for the physician to verify the correct positioning of the upper structure of the pessary relative to the cervix, at least without further discomfiting the patient.
Following the discovery that these devices offered some relief to certain incontinent women, and following sophisticated research to determine the mechanism by which this relief was obtained, there have been attempts to produce articles more suited to routine intravaginal use for control of incontinence. One relatively promising line of approach has involved molded pessaries. These were made of heat-softenable materials so that they could be immersed in warm water and then narrowed, lengthened, widened or shortened by manual kneading to more nearly match the shape of the vaginal canal.
All these attempts have met with little success. Prior-art pessaries have been problematic either in terms of discomfort, pressure necrosis and ulceration, if they have been made adequately tight-fitting; or in terms of expulsion with any sudden increase of intraabdominal pressure, such as coughing, if they are not tight enough.
Such disadvantages are virtually predictable from the overall demands placed upon prior-art pessaries: they are inherently subject to opposing constraints or expectations that have not been satisfactorily resolved. In particular, such pessaries are required to laterally engage the vagina by friction to hold themselves in place, but nevertheless to be slidable all the way up into the vagina for maximal elevating effect. Furthermore such pessaries are expected to conform to the internal shape of the vagina, for a reasonable degree of patient comfort; but also nevertheless to be readily removed and replaced, for a reasonable degree of sanitation. None of the prior-art pessaries has been conceptualized with an adequate eye to these intrinsic conflicting requirements.
Some patients have used tampons to elevate the vagina, but in protracted use these have caused problems because of their highly absorbent materials, leading to excessive dryness and consequent irritation of the vagina. To avoid these problems a foam-rubber substitute has been introduced. Its efficacy is not yet reported, but it does not extend fully into the most proximal portion of the vagina, behind the cervix, and therefore does not achieve optimal elevation of the vagina and urethra. Moreover, by the reasoning outlined in the preceding paragraph such a device is inherently likely to be either inadequate in elevating the vagina and urethra, and possibly difficult to keep in place, or traumatic to the vagina and difficult to keep clean.
Although pessaries thus have been relatively problematic as therapeutic prosthetics, their use in diagnosis has been proposed. Doctors Bergman and Bhatia, for example, have reported evaluation of the "pessary test" as a clinical tool to predict successful outcome of impending antiincontinence surgery. XXIV Urology 109 (July 1984).
In this research it was observed that the patterns of intraabdominal, intravesical, and intraurethral pressure observed with a pessary emulated to a certain degrees the corresponding patterns observed after surgery. This report is limited, however, to a statement that the pressures observed after surgery "were found to be very similar" to the corresponding pressures observed with a pessary emplaced before surgery. No patient-by-patient comparisons, no numerical abstractions, no control tests (i.e., patients with bladder instability or other nonanatomical syndrome), and no actual clinical effort to screen patients based upon a "pessary test" were reported.
(g) Antiincontinence Prosthetic Therapy: the Bonnar Inflatable Urethral Dam--A more direct approach to controlling incontinence is to obstruct the urethra. One device that aims to accomplish this is known as the "Bonnar device"--a partially inflatable article of soft silicone rubber. This device consists of an inflatable generally spherical main body and noninflatable rabbit-ear-shaped protrusions that fit into the lateral fornices of the vagina. (These are the most proximal region of the vagina, adjacent the cervix.)
The device is stabilized within the patient's vagina by the fornical protrusions, while the primary spherical section of the device when inflated presses forcibly against the wall between the vagina and the urethra. This inflated spherical section actually operates as a prosthetic sphincter, squeezing the urethral channel against the bone structure posterior to the urethra and thus directly blocking the urethra.
Unfortunately, unlike the natural urethral sphincter, this prosthesis is not remote controlled; consequently the Bonnar device must be deflated when the patient wishes to void. It must also be reinflated afterward. Although the device need not be extracted for this purpose, even the necessity of deflating and reinflating it is particularly objectionable since these steps severely encumber the patient's ability to approximate normal toilet behavior. For most patients this requirement would constitute an extremely undesirable limitation on the regular pursuit of ordinary daily activities.
It has been reported in one test of twenty research subjects that commercial versions of the Bonnar device were too large or too small for eight individuals, were totally ineffective in more than ten individuals, and were rejected for personal use after the trial by eighteen.
The Bonnar device is of interest here only because part of it is inflated within the vagina, and because it is intended to alleviate incontinence. Although it has been misdescribed in some literature as producing "elevation" of the urethra, this device actually does no such thing, but rather operates by direct occlusion in lieu of the normal sphincter, as already stated.
(h) Other Related Devices--Two other clinical articles should be mentioned briefly because they are inflatable and are inserted into the vagina, though their purposes and functions are quite different from those of the present invention.
One of these devices is known as the balloon of Kegel. It is placed in the vagina and connected to a manometer or other pressure meter, to measure the pressure with which a post-childbirth patient is able to "squeeze" inwardly with the vagina. This monitoring was initially introduced as part of a program (familiarly known as "Kegel's exercises") to determine postpara improvement in muscle tone. The balloon is inflated for the measurements, kept attached to the manometer during the monitoring, and immediately afterward deflated and removed from the patient. To make these measurements there is no particular need to advance the balloon fully into any well-defined position within the vagina. Only a physician normally performs the insertion, inflation, deflation, and removal.
Another device, which like Kegel's balloon has fallen rather out of popularity, is a balloon with attached button-like electrical contacts in its exterior surface. This article is part of a system used for artificially stimulating and thus exercising the muscles of the pelvic floor. The balloon is quite short, and many patients find the electrical button contacts--even when not energized--quite uncomfortable.